CN104674454B - Method for manufacturing three-dimensional porous disorder scaffolds from polylactic acid molten spinning fibers by means of thermal bonding and solidifying - Google Patents

Abstract

The method for preparing polylactic acid melt-spun fibers thermally bonded and solidified three-dimensional porous disordered scaffolds disclosed by the invention comprises the following steps: preparing melt-spun fibers and The fiber aggregates arranged in parallel are made by the yarn winding process; then the parallel arrayed fiber aggregates are cut into short fibers of different lengths, and the disordered scaffolds are prepared by uniform laying and thermal bonding and curing. Alternatively, slice polylactic acid with good biodegradability and biocompatibility, use a single-screw plastic extruder, and use self-thermal bonding through a melt-blown process to obtain a disordered scaffold. The PLA melt-spun fiber prepared by the method of the invention has a stable three-dimensional porous and disordered scaffold structure, and has better internal pore structure, physical properties and mechanical properties. The disordered scaffold can be applied in biomedical fields such as bone tissue engineering, and has good application potential and prospects.

Description

Preparation method of polylactic acid melt-spun fibers thermally bonded and solidified three-dimensional porous disordered scaffolds

technical field

The invention relates to a method for preparing a polylactic acid melt-spun fiber thermally bonded and solidified three-dimensional porous disordered scaffold.

Background technique

Fedorova et al., North Carolina State University Nonwovens Research Center [Fedorova N, Pourdeyhimi B: High strength nylon micro-and nanofiber based nonwovens viaspunbonding. J Appl Polym Sci 2007,104(5):3434-3442.] Nylon 6 (N6) and PLA (Natureworks) were used to prepare different island-in-the-sea fibers (Nylon 6 is the island, PLA is the sea), and then the fiber web was reinforced into a fabric by 30m/min hydroentanglement. Then the fabric was treated with 3% NaOH solution at 100° C. for 10 minutes to remove the PLA component. After dissolving the PLA component, micron and nanofibers can be obtained, and the fiber diameter can reach 0.36-1.3mm.

Regarding PLA melt-spun fibers, there are also Polypropylene/Poly(lactic acid) (PP/PLA) bicomponent fibers [Arvidson SA, Roskov KE, Pate JJ, Spontak RJ, Khan SA, Gorga RE: Modification of Melt-Spun Isotactic Polypropylene and Poly(lactic acid)Bicomponent Filamentswith a Premade Block Copolymer.Macromolecules 2012,45(2):913-925.; Liu Y,ToviaF,Pierce JD:Consumer Acceptability of Scent-infused Knitting Scarves UsingFunctional Melt-spun PP/PLA Bicomponent Fibers .Text Res J2009,79(6):566-573.], poly(lactic acid)/hydroxyapatite(PLA/HA)[Persson M,Lorite GS,Cho SW,Tuukkanen J,Skrifvars M:Melt Spinning of Poly(lactic acid) and HydroxyapatiteComposite Fibers: Influence of the Filler Content on the Fiber Properties.AcsAppl Mater Inter 2013,5(15):6864-6872.], poly(lactic acid)/Poly(R)-3-hydroxybutyrate-co-R -3-hydroxyvalerate(PLA/PHBV)[Pivsa-Art S,Srisawat N,O-Charoen N,Pavasupree S,Pivsa-Art W:Preparation of Knitting Socks from Poly(lactic acid)and Poly[(R)-3- hydroxybutyrate-co-(R)-3-hydroxyvalerate](PHBV)blends for Textile Industries.Enrgy Proced 2011,9.], poly(lactic acid)/polyvinylidene fluoride(PLA/PVDF)[Fryczkowski R, Fryczkowska B, Binias W, Janicki J: Morphology of fibrous composites of PLA and PVDF.Compos Sci Technol2013,89:186-193.], Polylactide/Multiwall Carbon Nanotube (PLA/MWNT) [Rizvi R, Tong L, Naguib H: Processing and Properties of Melt Spun Polylactide-Multiwall Carbon Nanotube Fiber Composites.J Polym Sci Pol Phys 2014,52(6):477-484.], Polylactide/ poly(vinyl alcohol)(PLA/PVA)[Tran NHA,Brunig H,Hinuber C,HeinrichG:Melt Spinning of Biodegradable Nanofibrillary Structures from Poly(lactic acid)and Poly(vinyl alcohol)Blends.Macromol Mater Eng 2014,299(2) :219-227.], Polylactide/poly(butylene succinate)(PLA/PBS)[Jompang L, Thumsorn S, On JW, Surin P, Apawet C, Chaichalermwong T, Kaabbuathong N, O-Charoen N, Srisawat N: Poly (lactic acid) and Poly(butylene succinate) Blend Fibers Prepared by MeltSpinning Technique. 10th Eco-Energy and Materials Science and Engineering Symposium 2013,34:493-499.].

In addition, some researchers have processed PLA into fabrics (woven fabrics, knitted fabrics, three-dimensional orthogonal fabrics), nonwovens (meltblown nonwovens, spunbonded nonwovens, needle punched nonwovens, thermally bonded nonwovens, etc.) cloth and electrospun nanofiber nonwovens), composites, films, etc.

Dai et al.[Dai XJJ,du Plessis J,Kyratzis IL,Maurdev G,Huson MG,CoombsC:Controlled Amine Functionalization and Hydrophilicity of a Poly(lactic acid)Fabric.Plasma Process Polym2009,6(8):490-497.] The PLA melt-spun fibers were prepared into knitted fabrics and then treated with plasma. Bae et al.[Bae GY,Jang J,Jeong YG,Lyoo WS,Min BG:Superhydrophobic PLA fabrics prepared by UV photo-grafting of hydrophobicsilica particles possessing vinyl groups.J Colloid Interf Sci 2010,344(2):584-587 .] Using ultraviolet irradiation technology to graft hydrophobic silica particles on the surface of PLA fabrics to prepare superhydrophobic fabrics. Nodo et al.[Nodo K,Leong YW,Hamada H:Effect of knitted and woven textile structures on the mechanical performance of poly(lactic acid)textile insertion-compression moldings.J Appl Polym Sci 2012,125:E200-E207.]Research The loading properties of PLA woven and knitted fabrics in impact tests, the results show that the PLA fabrics prepared by compression molding have better toughness and extensibility. In addition, there are PLA three-dimensional orthogonal fabrics [Zhou NT, Geng XY, Ye MQ, Yao L, Shan ZD, QiuYP: Mechanical and sound adsorption properties of cellular poly(lactic acid) matrix composites reinforced with 3D ramie fabrics woven with co- wrappedyarns. Ind Crop Prod 2014, 56:1-8.].

Melt-blown technology is to prepare thermoplastic polymers into ultra-fine fiber non-woven fabrics with high-speed airflow. This non-woven fabric has smaller pore size and larger porosity. Liu et al.[Liu Y, Cheng BW, Cheng GX: Development and Filtration Performance of Polylactic Acid Meltblowns. Text Res J 2010,80(9):771-779.] Sliced PLA from Natureworks (T _g ＝52℃, T _m = 168°C) to prepare PLA melt-blown nonwovens through drying, melt extrusion, filtration, gear metering, spinning, hot air stretching, cooling and winding reception in sequence. The receiving distance is 20cm, the hot air pressure is 0.15MPa, the spinning temperature is 220°C, the hot air temperature is 250, 260, 270, 280, 290, and 300°C, and the slit width is 0.3, 0.4, 0.5, and 0.6 cm. And the changes of hot air temperature (250-290°C) and slit width (0.3-0.6cm) on the fiber diameter, porosity, average pore size, and filtration of 0.3 μm and 0.5 μm particles of PLA meltblown nonwovens were studied respectively. The influence and change rule of efficiency and air flow. Majchrzycka[MajchrzyckaK:Evaluation of a New Bioactive Nonwoven Fabric for RespiratoryProtection.Fibres Text East Eur 2014,22(1):81-88.] Using Natureworks PLA slices (T _m =160-170°C), spinning at 270°C Temperature, hot air temperature of 270°C, air flow rate of 8.8m ³ /h, receiving distance of 300mm to prepare PLA melt-blown nonwovens, and use biologically active substances to modify PLA melt-blown nonwovens, and at the same time study bacteria in Survivability on the bioactive nonwoven and aerosol filtration efficiency. Cerkez et al. [CerkezI, Worley SD, Broughton RM, Huang TS: Rechargeable antimicrobial coatings for poly(lactic acid)nonwoven fabrics. Polymer 2013,54(2):536-541.] University of Tennessee Textile and Nonwovens Development Center The provided PLA meltblown nonwoven fabric (30 g/m ² ) was coated with a homopolymer of heterocyclic N-haloamine acetate (1.5 wt%, 40° C., 10 min). Experimental results show that the coating is very stable and has high antibacterial properties against Staphylococcus aureus and Escherichia coli. The coated scaffold could be used in antimicrobial food packaging, filters and hygiene products. Krucinska et al.[Krucinska I, Surma B, Chrzanowski M, Skrzetuska E, Puchalski M: Application of melt-blown technology in the manufacturing of solvent vapor-sensitive, non-woven fabric composed of poly(lactic acid) loaded with multi-walled carbon nanotubes.Text Res J 2013,83(8):859-870.] For the first time, 98% PLA/2% multi-walled carbon nanotubes (MWCNTs) melt-blown nonwovens were prepared.

Puchalski et al. [Puchalski M, Krucinska I, Sulak K, Chrzanowski M, Wrzosek H: Influence of the calender temperature on the crystallization behaviors of polylactide spun-bonded non-woven fabrics. Text Res J 2013,83(17):1775- 1785.] Dried the PLA chip 6251D (Mn=45800g/mol, _Tg =61°C, _Tm =168°C) of American Natureworks at 80°C for 4h, the spinning temperature was 205-216°C, the production capacity of the polymer 0.10-0.43g/min/Hole, the spinneret has 467 holes in total, and the hot pressing temperature is 60-130°C. The internal morphology, crystallinity, physical-mechanical properties and thermal degradation properties of PLA spunbond nonwovens were studied at different hot-pressing temperatures. Gutowska et al.[Gutowska A,Jozwicka J,Sobczak S,Tomaszewski W,Sulak K,Miros P,Owczarek M,Szalczynska M,Ciechanska D,Krucinska I:In-Compost Biodegradation of PLA Nonwovens.FibresText East Eur 2014,22( 5): 99-106.] Using Natureworks PLA slices (T _m =160-170°C), spinning temperature of 212±1°C, take-up roll at a speed of 2.9-6.8m/min, 42.4-101.8g/min The extrusion throughput, thermal bonding temperature of 60-105°C and pressure of 1500-2000Pa were used to prepare PLA spunbonded nonwovens and study their degradation performance in an environment of 58±2°C, pH=7 and 52.6% humidity. Wang et al. [Wang HB, Wei QF, Wang X, Gao WD, Zhao XY: Antibacterial properties of PLA nonwoven medical dressings coated with nanostructured silver. Fiber Polym2008, 9(5): 556-560.] The PLA spunbonded nonwoven fabric (35g/m ² ) provided by Woven Cloth Co., Ltd. was immersed in acetone solution, then ultrasonically rinsed for 30 minutes to remove the organic solvent, washed twice with plasma water, and dried in an oven at 30-35°C. The magnetron sputtering coating system of argon plasma was used to plate silver on it to obtain PLA spunbond nonwovens coated with nano silver, and the influence of nano coating thickness on the antibacterial properties of nonwovens was studied. Experimental results show that when the thickness of the coating is 1nm, the antibacterial effect on Staphylococcus aureus and Escherichia coli can reach 100%.

Yilmaz et al.[Yilmaz ND,Banks-Lee P,Powell NB,Michielsen S:Effects of Porosity,Fiber Size,and Layering Sequence on Sound Absorption Performance ofNeedle-Punched Nonwovens.J Appl Polym Sci 2011,121(5):3056- 3069.] The PLA fibers of Johnson Fiber’s innovative technology in the United States were sequentially subjected to Truetzschler fiber opening, air-laid and needle-punched reinforcement processes to prepare multi-layer composite PLA needle-punched nonwovens, and their thickness, weight, porosity and airflow were studied. resistance. 10-20mm PLA melt-spun monofilaments were cut, carded, and needle-punched to prepare PLA needle-punched nonwovens, and then modified with chondroitin sulfate and conductive polypyrrole (polypyrrole, PPy) coating to prepare bone-forming scaffolds. The experimental results showed that compared with the uncoated PLA needle-punched nonwovens, the coated conductive scaffolds could improve the proliferation and osteogenic differentiation of human adipose stem cells under electrical stimulation. And the conductivity of the coated conductive scaffolds was significant at the beginning of hydrolysis, but began to decline after one week of incubation. This coated conductive scaffold can be applied in bone tissue engineering.

Bhat et al. [Bhat GS, Gulgunje P, Desai K: Development of structure and properties during thermal calendering of polylactic acid (PLA) fiberwebs. Express Polym Lett 2008, 2 (1): 49-56.] PLA staple fiber (fiber Length is 76mm, and fineness is 3denier) Utilize SDS Atlas carding machine to form the fiber web that weight is 35g/m ² after carding, and fiber web size is 120cm * 30cm, then fiber web is compounded by hot rolling (hot rolling temperature is higher than fiber The glass transition temperature is lower than the melting point, which is 130-150°C). During the hot rolling process, the speed and pressure of the hot pressing rolls were kept constant to prepare PLA short fiber nonwovens.

Wakita et al.[Wakita T,Obata A,Poologasundarampillai G,Jones JR,Kasuga T:Preparation of electrospun siloxane-poly(lactic acid)-vateritehybrid fibrous membranes for guided bone regeneration.Compos Sci Technol2010,70(13):1889- 1893.] The siloxane-poly(lactic acid)(PLA)-vaterite composite nonwoven fabric was prepared by electrospinning method as a scaffold for guiding bone regeneration, and the hydroxyapatite (HA) coating was used to improve the cytocompatibility of the fabric. The experimental results show that the coated composite nonwoven has the ability to release soluble silicon and calcium, which can stimulate osteoblasts at the gene level. And this porous scaffold has a smaller pore size that can prevent the entry of soft tissue, promote bone formation and ion release, and enhance bone growth at the same time. Chen et al.[Chen HC, Tsai CH, Yang MC: Mechanical properties and biocompatibility of electrospunpolylactide/poly(vinylidene fluoride)mats.J Polym Res 2011,18(3):319-327.] Combining PLA with poly(vinylidene fluoride) )(PVDF) were mixed and dissolved in the common solvent N,N-dimethylformamide and acetone for electrospinning to prepare nanofiber nonwovens with different mixing ratios, and to study fiber morphology, contact angle, thermal properties, Tensile properties, hemocompatibility and cytocompatibility. The experimental results show that, compared with PLA and PVDF nonwovens, PLA/PVDF composite nonwovens have better fibroblast proliferation ability and application potential. Au et al.[Chen HC, Tsai CH, Yang MC: Mechanical properties and biocompatibility of electrospun polylactide/poly(vinylidene fluoride)mats.J Polym Res 2011,18(3):319-327.] were prepared by electrospinning technology Polylactic acid/chitosan (PLA/CS) and polylactic acid/chitosan/nano-silver (PLA/CS/Ag) nonwovens were tested, and the experimental results showed that electrospun nonwovens containing nano-silver had anti-Escherichia coli and Good antibacterial properties of Staphylococcus aureus. Haroosh et al.[Haroosh HJ,Dong Y,Ingram GD:Synthesis,Morphological Structures,and Material Characterization of Electrospun PLA:PCL/Magnetic Nanoparticle Composites for Drug Delivery.JPolym Sci Pol Phys 2013,51(22):1607-1617.] Magnetic nanoparticles (MPs) were added to poly(lactic acid)(PLA):poly(e-caprolactone)(PCL) solution for electrospinning to prepare composite nonwovens, and tetracycline hydrochloride was added to the composite to study drugs Unleash performance. The experimental results are consistent with previous research theories, indicating that the composite nonwoven has good drug release performance and can be used in drug delivery. Casasola et al. [Casasola R, Thomas NL, Trybala A, Georgiadou S: Electrospun poly lactic acid (PLA) fibers: Effect of different solvent systems on fiber morphology and diameter. Polymer 2014,55(18):4728-4737.] The electrospinnability, fiber morphology, viscosity, conductivity and surface tension of PLA in different solvents were studied. The experimental results showed that, among all the solvents, acetone/dimethylformamide had higher production efficiency and produced the best nanofibers without defects (beaded morphology). Parwe et al.[Parwe SP,Chaudhari PN,Mohite KK,Selukar BS,Nande SS,Garnaik B:Synthesis of ciprofloxacin-conjugated poly(L-lactic acid)polymer for nanofiber fabrication and antibacterial evaluation.Int J Nanomed 2014,9:1463- 1477.] Prepare ciprofloxacin and PLA by electrospinning to prepare nanofiber composite membrane, the fiber diameter is 150-400nm, and the pore diameter is 62-102nm. The experimental results show that the composite film has a good ability to release ciprofloxacin and inhibit the growth of Staphylococcus aureus and Escherichia coli. This biodegradable ciprofloxacin-nanofiber nonwoven can be used in drug delivery. Li et al.[Li DP, Frey MW, Baeumner AJ: Electrospun polylactic acid nanofiber membranes as substrates for biosensor assemblies.J MembraneSci 2006,279(1-2):354-363.] Adding biotin to PLA spinning solution Electrospinning was performed to prepare nanofibrous membranes for biosensors.

Moran et al. [Moran JM, Pazzano D, Bonassar LJ: Characterization of polylactic acid polyglycolic acid composites for cartilage tissue engineering. Tissue Eng 2003,9 (1): 63-70.] Polyglycolic acid (PGA) nonwoven fabric (fiber diameter 15mm, porosity > 95%) were cut into small pieces, and then coated with 1mL of 0.5, 1.0, 2.0 and 3.0% PLA solution (PLA dissolved in methylene chloride) respectively, and then the scaffold was dried and tested for performance And the growth of bovine articular chondrocytes on polylactic acid (PLA)/polyglycolic acid (PGA) composites was studied. The experimental results showed that the cells showed a flat shape on PGA, while they were more rounded on PLA. This scaffold can be used in cartilage tissue engineering. In addition, there are PLA/flax composite nonwoven materials [Alimuzzaman S, Gong RH, Akonda M: Nonwoven Polylactic Acid and Flax Biocomposites. Polym Composite 2013,34(10):1611-1619.; Alimuzzaman S, Gong RH, Akonda M :Three-dimensional nonwoven flax fiber reinforced polylactic acid biocomposites.Polym Composite 2014,35(7):1244-1252.], PLA/hemp laminate composite [Song YS, Lee JT, Ji DS, Kim MW, Lee SH, Youn JR:Viscoelastic and thermalbehavior of woven hemp fiber reinforced poly(lactic acid)composites.ComposPart B-Eng 2012,43(3):856-860.], PLA/bamboo fiber fabric laminated composites [Porras A,MaranonA:Development and characterization of a laminate composite material frompolylactic acid(PLA)and woven bamboo fabric.Compos Part B-Eng 2012,43(7):2782-2788.], coconut fiber/PLA fiber composite material [Jang JY, Jeong TK, Oh HJ,Youn JR,Song YS:Thermal stability and flammability of coconut fiber reinforced poly(lactic acid)composites.Compos Part B-Eng 2012,43(5):2434-2438.], ramie fabric/PLA film laminated composites[ Zhou NT, Yao L, Liang YZ, Yu B, Ye MQ, Shan ZD, Qiu YP: Improvement of mechanical properties of ramie/poly(lactic acid)(PLA)laminated composite susi ng a cyclic load pre-treatment method.Ind Crop Prod 2013,45:94-99.], kenaf/PLA composite electronic materials [Serizawa S, Inoue K, Iji M: Kenaf-fiber-reinforced poly(lactic acid) used for electronic products.J Appl Polym Sci 2006,100(1):618-624.], hemp/PLA biodegradable composites [Hu R,Lim JK:Fabrication and mechanical properties of completely biodegradable hemp fiber reinforced polylactic acid composites.JCompos Mater 2007 , 41(13):1655-1669.].

Tingaut et al.[Tingaut P, Zimmermann T, Lopez-Suevos F:Synthesis and Characterization of Bionanocomposites with Tunable Properties from Poly(lactic acid)and Acetylated Microfibrillated Cellulose.Biomacromolecules2010,11(2):454-464.]Dissolve PLA in In chloroform (2% w/w), and with PLA as the matrix and acetylated microfibrils (MFC) as the reinforcement to prepare bionanocomposites. Experimental results show that this biocomposite has good thermal stability and hygroscopicity.

Due to the development prospects and application potential of disordered scaffolds, as well as the inadequacies of methods for preparing disordered scaffolds in previous literatures, the present invention attempts to prepare disordered scaffolds by using thermal bonding of PLA melt-spun fibers.

Contents of the invention

The purpose of the present invention is to provide a kind of polylactic acid melt-spun fiber thermally bonded and solidified three-dimensional porous polylactic acid melt-spun fiber that is simple and easy to implement, meets the requirements of environmental protection, and has tight adhesion between polylactic acid melt-spun fibers, no detachment, and good formability Preparation of disordered scaffolds.

The preparation method of the polylactic acid melt-spun fiber thermally bonded and solidified three-dimensional porous disordered scaffold has the following two technical solutions:

plan 1:

A method for preparing a polylactic acid melt-spun fiber thermally bonded and solidified three-dimensional porous disordered scaffold comprises the following steps:

1) Polylactic acid chips with good biodegradability and biocompatibility are prepared into fibers by melt spinning;

2) the polylactic acid fiber prepared in step 1) is 999-1001mm in circumference and 3-4cm in width with a skein length measuring instrument, with a speed of 1-300r/min and an initial tension of 100cN. The fibers are wound in parallel to obtain ordered fiber bundles of polylactic acid;

3) Cut the polylactic acid ordered fiber bundle prepared in step 2) into short fibers with a length of 1-4 cm, and then evenly spread the short fiber aggregates into a net shape, at a temperature of 60-140 ° C, a pressure of 13 × 10 ⁶ Pa , hot pressing for 1-60min to obtain a three-dimensional porous and disordered scaffold;

Or cut the polylactic acid ordered fiber bundle prepared in step 2) into short fibers with a length of 1-4 cm, and then evenly spread the short fiber aggregates into a net, at a temperature of 60-140 ° C and a pressure of 13 × 10 ⁶ Pa , hot pressing for 1-60 min, then cold pressing for 1-5 min at 0°C and 1-13×10 ⁶ Pa pressure conditions for bonding, and then naturally cooled to room temperature to obtain a three-dimensional porous disordered scaffold.

Scenario 2:

A method for preparing a polylactic acid melt-spun fiber thermally bonded and solidified three-dimensional porous disordered scaffold comprises the following steps:

Sliced polylactic acid with good biodegradability and biocompatibility, using a single-screw plastic extruder, the screw length-to-diameter ratio L/D=28:1, the drum speed is 21.0rpm, and the traverse speed is 38.8cm/min , the screw speed is 5.65r/min, the diameter of the spinneret hole is 0.02mm, the temperature of the spinning die is 250°C, the temperature of the hot air is 320°C, the pressure of the hot air is 0.3MPa, the receiving between the spinneret and the receiving drum The distance is 75-200mm, and a three-dimensional porous and disordered scaffold is obtained by self-thermal bonding.

In the present invention, the molecular weight of the polylactic acid (PLA) is 170,000-200,000.

The beneficial effects of the present invention are:

The method of the invention is simple and easy, has no pollution, and the polylactic acid melt-spun fibers are tightly bonded without detachment and good formability, and can meet the needs of industrial application. The method of preparing three-dimensional porous disordered scaffolds by thermal bonding and solidification of polylactic acid melt-spun fibers can be similar to the preparation of melt-spun fibers of other high polymers (such as polycaprolactone, polyglycolic acid, polyethylene glycol, polyurethane, etc.) The brackets are provided for reference. The polylactic acid melt-spun fiber disordered scaffold prepared by the preparation method has good internal pore structure, physical properties and mechanical properties, and has good application potential, and can be used as a biomaterial in bone tissue engineering.

Description of drawings

FIG. 1 is a scanning electron micrograph of the surface of the PLA melt-spun fiber disordered scaffold prepared in Example 1.

FIG. 2 is a scanning electron micrograph of the cross-sectional shape of the disordered scaffold of PLA melt-spun fibers prepared in Example 1. FIG.

Fig. 3 is a scanning electron micrograph of the surface of the PLA melt-spun fiber disordered scaffold prepared in Example 2.

FIG. 4 is a scanning electron micrograph of the cross-sectional shape of the disordered scaffold of PLA melt-spun fibers prepared in Example 2. FIG.

Fig. 5 is a scanning electron micrograph of the surface of the PLA melt-spun fiber disordered scaffold prepared in Example 3.

6 is a scanning electron micrograph of the cross-sectional shape of the disordered scaffold of PLA melt-spun fibers prepared in Example 3.

FIG. 7 is a scanning electron micrograph of the surface of the PLA melt-spun fiber disordered scaffold prepared in Example 4. FIG.

8 is a scanning electron micrograph of the cross-sectional shape of the disordered scaffold of PLA melt-spun fibers prepared in Example 4.

FIG. 9 is a scanning electron micrograph of the surface of the PLA melt-spun fiber disordered scaffold prepared in Example 5. FIG.

FIG. 10 is a scanning electron micrograph of the cross-sectional shape of the disordered scaffold of PLA melt-spun fibers prepared in Example 5.

FIG. 11 is a scanning electron micrograph of the surface of the PLA melt-spun fiber disordered scaffold prepared in Example 6. FIG.

Fig. 12 is a scanning electron micrograph of the cross-sectional shape of the disordered scaffold of PLA melt-spun fibers prepared in Example 6.

detailed description

Below in conjunction with embodiment further illustrate the present invention.

Example 1:

PLA chips with a molecular weight of 170,000 were melt-spun to prepare PLA fibers with an average diameter of 12.41 μm; a YG086 skein length measuring instrument was used to wind 1,000 aggregates arranged in parallel at a speed of 300 r/min, and the circumference of the yarn frame It is 1000mm, the width is 3.5cm, and the initial tension is 100cN. The ordered PLA melt-spun fiber bundles arranged in parallel were cut 10 times with scissors, and cut into 10,000 short fibers with a length of 1 cm. Then, 10,000 1cm short fiber aggregates were uniformly laid, and then hot-pressed and cold-pressed. The hot-pressing temperature was 60°C, the hot-pressing time was 5 minutes, the hot-pressing pressure was 13×10 ⁶ Pa, and the cold-pressing temperature was 0 ℃, the cold pressing time is 5 min, and the cold pressing pressure is 13×10 ⁶ Pa. Then cooled naturally to room temperature to obtain a three-dimensional porous disordered scaffold.

The surface and cross-sectional morphology of the PLA melt-spun fiber three-dimensional porous disordered scaffold prepared in this example are shown in Figures 1 and 2 . It can be seen from the figure that the PLA melt-spun fibers in this three-dimensional porous and disordered scaffold are arranged randomly and disorderly, with an average thickness of 0.02cm, a weight of 0.0054g/cm ² , an order degree of 81.7°, and an average pore diameter of 17.8 μm, the porosity is 54.4%, and the connectivity between pores is good. The tensile stress and strain of the scaffold along the fiber alignment direction are 0.0026MPa and 48.9%, respectively.

Example 2:

The method is the same as in Example 1, except that the length of short PLA melt-spun fibers is changed to 2 cm. The surface and cross-sectional morphology of the PLA melt-spun fiber three-dimensional porous disordered scaffold prepared in this example are shown in FIGS. 3 and 4 . It can be seen from the figure that the PLA melt-spun fibers in this disordered scaffold are arranged randomly and disorderly, with an average thickness of 0.056 cm, a weight of 0.019 g/cm ² , an order degree of 70.2°, and an average pore size of 20.9 μm. The porosity is 65.9%, and the inter-pore connectivity is good. The tensile stress and strain of the scaffold along the fiber alignment direction are 0.04MPa and 73.3%, respectively.

Example 3:

The method is the same as in Example 1, except that the length of short PLA melt-spun fibers is changed to 4 cm. The surface and cross-sectional morphology of the PLA melt-spun fiber three-dimensional porous disordered scaffold prepared in this example are shown in FIGS. 5 and 6 . It can be seen from the figure that the PLA melt-spun fibers in this disordered scaffold are randomly arranged in disorder, with an average thickness of 0.092 cm, a weight of 0.039 g/cm ² , an order degree of 37.3°, and an average pore size of 19.8 μm. The porosity is 74%, and the inter-pore connectivity is good. The tensile stress and strain of the scaffold along the fiber alignment direction are 0.16MPa and 126.2%, respectively.

Example 4:

Slice PLA with a molecular weight of 170,000 and use a SJ-30/28 single-screw plastic extruder with a screw length-to-diameter ratio of L/D=28:1. The rotating speed of the drum is 21.0 rpm, the traverse speed is 38.8 cm/min, the rotating speed of the screw is 5.65 r/min, and the diameter of the spinneret hole is 0.02 mm. The temperature of the spinning die is 250° C., the temperature of the hot air is 320° C., the pressure of the hot air is 0.3 MPa, and the receiving distance between the spinneret and the drum is 75 mm. A three-dimensional porous and disordered PLA scaffold with a fiber diameter of 3 μm was obtained by self-thermal bonding without hot pressing and cold pressing.

The surface and cross-sectional morphology of the PLA melt-spun fiber three-dimensional porous disordered scaffold prepared in this example are shown in FIGS. 7 and 8 . It can be seen from the figure that the PLA melt-spun fibers in this disordered scaffold are randomly arranged in disorder, with an average thickness of 0.12 cm, a weight of 0.014 g/cm ² , an order degree of 73.5°, and an average pore size of 19.7 μm. The porosity is 59.8%, and the inter-pore connectivity is good. The tensile stress and strain of the scaffold along the fiber alignment direction are 0.059MPa and 70.7%, respectively.

Embodiment 5:

The method is the same as that in Embodiment 4, except that the receiving distance is changed to 100mm. A PLA three-dimensional porous disordered scaffold with a fiber diameter of 5.3 μm was obtained. The surface and cross-sectional morphology of the PLA melt-spun fiber disordered scaffold prepared in this example are shown in FIGS. 9 and 10 . It can be seen from the figure that the PLA melt-spun fibers in this disordered scaffold are arranged randomly and disorderly, with an average thickness of 0.072cm, a weight of 0.0093g/cm ² , an order degree of 60.2°, and an average pore size of 17.8μm. The porosity is 65.4%, and the inter-pore connectivity is good. The tensile stress and strain of the scaffold along the fiber alignment direction are 0.028MPa and 58.5%, respectively.

Embodiment 6:

The method is the same as that in Embodiment 4, except that the receiving distance is changed to 200mm. A PLA three-dimensional porous disordered scaffold with a fiber diameter of 5.3 μm was obtained. The surface and cross-sectional morphology of the PLA melt-spun fiber disordered scaffold prepared in this example are shown in FIGS. 11 and 12 . It can be seen from the figure that the PLA melt-spun fibers in this disordered scaffold are randomly arranged in disorder, with an average thickness of 0.13 cm, a weight of 0.012 g/cm ² , an order degree of 79.2°, and an average pore diameter of 13 μm. The ratio is 51.2%, and the connectivity between pores is good. The tensile stress and strain of the scaffold along the fiber alignment direction are 0.035MPa and 53.5%, respectively.

Claims (2)

1. The preparation method of polylactic acid melt-spinning fiber heat-bonded and solidified three-dimensional porous disordered support is characterized in that it comprises the steps: 1) Polylactic acid chips with good biodegradability and biocompatibility are prepared into fibers by melt spinning; 2) With the polylactic acid fiber prepared in step 1), use a skein length measuring instrument on a yarn frame with a circumference of 999-1001mm and a width of 3-4cm, at a speed of 1-300 r/min and an initial tension of 100cN, Winding the fibers in parallel to obtain ordered fiber bundles of polylactic acid; 3) Cut the polylactic acid ordered fiber bundle prepared in step 2) into short fibers with a length of 1-4cm, and then evenly spread the short fiber aggregates into a net shape, at a temperature of 60-140°C and a pressure of 13×10 ⁶ Pa , hot pressing for 1-60min to obtain a three-dimensional porous and disordered scaffold; Or cut the polylactic acid ordered fiber bundle prepared in step 2) into short fibers with a length of 1-4cm, and then spread the short fiber aggregates evenly into a net, at a temperature of 60-140°C and a pressure of 13×10 ⁶ Pa , hot pressing for 1-60 min, followed by cold pressing for 1-5 min at 0°C and 1-13×10 ⁶ Pa pressure conditions for bonding, and then naturally cooled to room temperature to obtain a three-dimensional porous disordered scaffold. 2. The preparation method of the polylactic acid melt-spun fiber thermally bonded and solidified three-dimensional porous disordered scaffold according to claim 1, characterized in that the molecular weight of the polylactic acid is 170,000-200,000.